Почему не видно устройства, и как исправить это?

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
MODULE_LICENSE("Dual BSD/GPL");

dev_t dev;
unsigned baseminor = 0;
unsigned count = 1;
unsigned scull_major = 0;
char *name = "scull";
struct cdev *cdev;
struct scull_dev {
	int quantum;
	int qset;
	unsigned long size;
	unsigned int access_key;
	struct semaphore sem;
	struct cdev cdev;
};
struct scull_dev sdev;

loff_t scull_llseek ( struct file *file, loff_t pos, int n )
{
}
ssize_t scull_read ( struct file *file, char __user *usr, size_t count, loff_t *pos)
{
}
ssize_t scull_write ( struct file *file, const char __user *usr, size_t n, loff_t *lt )
{
}
int scull_open ( struct inode *inode, struct file *filp )
{
	struct scull_dev *scdev;

	scdev = container_of ( inode->i_cdev, struct scull_dev, cdev );
	filp->private_data = scdev;

	return 0;
}
struct file_operations scull = {
	.owner = THIS_MODULE,
	.llseek = scull_llseek,
	.read = scull_read,
	.write = scull_write,
	.open = scull_open
};

static int hello_init ( void )
{
	int err;
	int result = alloc_chrdev_region ( &dev, baseminor, count, name );
	scull_major = MAJOR(dev);
	cdev_init ( &sdev.cdev, &scull );
	sdev.cdev.owner = THIS_MODULE;
	sdev.cdev.ops = &scull;
	err = cdev_add ( &sdev.cdev, dev, 1 );
	if ( err )
		printk (KERN_NOTICE "Error %d adding scull%d", err, 0 );
	
}

static void hello_exit ( void )
{
	cdev_del ( &sdev.cdev );
	unregister_chrdev_region ( dev, count );
}

module_init ( hello_init );
module_exit ( hello_exit );